The article is in the EAA Aircraft Building Techniques Wood...
He mentions a Les Long ultra-light truss rib design....it uses four 1/4" x 1/4" spruce strips as double cap strips between which are slid the uprights and diagonals which are glued and held by a 3/4" 20 gauge nail. (no plywood gusset) You just stick them in long and trim them later with a knife/saw/router. Supposedly self gusseting (by the dual cap strips), takes only 10 minutes to make and a 54" chord design weighs about 3.5 ounces. Bingelis even says, "Maybe builders should take another look at this design."
Has anybody taken another look at it? I read "How to build the Longster" by Les Long (1931 Flying and Gliding Manual) and Long describes making the rib that way but gives no picture or sketch of the rib design, so I don't know how he arranged the uprights and diagonals...obviously they didn't buttress nicely together because they protrude out for trimming, so there is a gap between the upright and diagonal. How small or large the gap is, I have no idea, but with a gap it makes me think a regular truss/gusset design would be stronger, but heavier because of the gussets. Any thoughts on this? If I were to build a rib of this type and a regular gusset type, can anybody recommend test procedures to compare them?
I must admit, I find the 1930's '10 minutes to make' interesting, did they have nailguns back then? It might even be able to make one faster now.
And even if it is weaker, might there still be a place for it in light planes? I've read several concerns about how foam ribs glue joints fail. Might this be a safer replacement in a light plywood covered wing?
If it is weaker and lighter, but so quick to build, perhaps an increase in the number of ribs for wood/fabic wings? Perhaps only stitching every other rib? (no good making up time one way if you lose it another)
Any thoughts on this would be appreciated. I'm certainly up for building a few test ribs.
He mentions a Les Long ultra-light truss rib design....it uses four 1/4" x 1/4" spruce strips as double cap strips between which are slid the uprights and diagonals which are glued and held by a 3/4" 20 gauge nail. (no plywood gusset) You just stick them in long and trim them later with a knife/saw/router. Supposedly self gusseting (by the dual cap strips), takes only 10 minutes to make and a 54" chord design weighs about 3.5 ounces. Bingelis even says, "Maybe builders should take another look at this design."
Has anybody taken another look at it? I read "How to build the Longster" by Les Long (1931 Flying and Gliding Manual) and Long describes making the rib that way but gives no picture or sketch of the rib design, so I don't know how he arranged the uprights and diagonals...obviously they didn't buttress nicely together because they protrude out for trimming, so there is a gap between the upright and diagonal. How small or large the gap is, I have no idea, but with a gap it makes me think a regular truss/gusset design would be stronger, but heavier because of the gussets. Any thoughts on this? If I were to build a rib of this type and a regular gusset type, can anybody recommend test procedures to compare them?
I must admit, I find the 1930's '10 minutes to make' interesting, did they have nailguns back then? It might even be able to make one faster now.
And even if it is weaker, might there still be a place for it in light planes? I've read several concerns about how foam ribs glue joints fail. Might this be a safer replacement in a light plywood covered wing?
If it is weaker and lighter, but so quick to build, perhaps an increase in the number of ribs for wood/fabic wings? Perhaps only stitching every other rib? (no good making up time one way if you lose it another)
Any thoughts on this would be appreciated. I'm certainly up for building a few test ribs.
